Needle core biopsy instrument

ABSTRACT

A needle core biopsy instrument/extractor for extracting a tissue sample via needle aspiration is disclosed. The extractor comprises a first cannula having a sharpened, beveled cutting tip and biopsy reservoir formed on its distal end. The proximal end of the first cannula is in fluid communication with a conventional syringe such that when the plunger of the syringe is retracted via manipulation of the extractor, a vacuum is created within the biopsy reservoir of the first cannula. Axially mounted about the first cannula is a second cutting cannula which is designed and configured to selectively cover and uncover the distal end of the first cannula. A biasing member, preferably a spring, is provided to urge the second cannula forward about the distal end of the first cannula. The syringe, coaxially positioned first and second cannulas, and biasing member are contained within an introducer which is preferably designed and configured to be manipulated by one hand. The handle slide and lever of the device are oriented in such a way as to allow the retention of tissue via vacuum and the severing of the specimen by the second cannula to be exactly timed by cam operation.

FIELD OF THE INVENTION

The present invention relates to tissue extraction devices, and moreparticularly, to hand-held devices for extracting tissue samples byneedle aspiration.

BACKGROUND OF THE INVENTION

Biopsy devices utilizing needle aspiration to extract tissue samples arewell known to those skilled in the art. Such devices are extremelyuseful to obtain samples of tissue suspected as being cancerous so thatsuch tissue may be examined to confirm such suspected diagnosis. Suchdevices are especially used when sampling suspected cancerous tissue inthe lungs, breasts, and prostate, as well as other body organs. Numerousother applications have also been found for these devices.

Generally, such biopsy instruments extract a sample of tissue from atissue mass by either drawing a tissue sample into a hollow needle viaan external vacuum force or by severing and containing a tissue samplewithin a notch formed on a cannula. Typical of such devices utilizing avacuum force are U.S. Pat. No. 5,246,011 issued to Cailouette and U.S.Pat. No. 5,183,052 issued to Terwilliger. Such devices contemplate theuse of advancing a hollow needle into a tissue mass and applying avacuum force to draw a sample into the needle and hold the same thereinwhile the tissue is extracted. Such devices, however, fail to adequatelysever and contain such tissue samples as the vacuum force may not besufficiently strong enough to sever and hold the sample within thebiopsy needle.

Alternatively, other prior art biopsy instruments alternatively utilizea biopsy needle with a tissue sample recovery notch formed thereon toextract a specimen, such as described in U.S. Pat. No. 3,477,423 issuedto Griffith, often referred to as the TRU-CUT needle and U.S. Pat. No.4,776,346 issued to Beraha et al. Such devices, however, have thedrawback of not effectively drawing a tissue sample of sufficient sizeinto the biopsy notch on the cannula. Accordingly, such samplesextracted by such biopsy needles may not provide sufficient tissue toperform an examination and thus require additional biopsies to be taken.Additionally, such needles have the disadvantage of having to beadvanced into the desired tissue site such that the needle may possiblyextend beyond the tissue site, thus resulting in the recovery of aninaccurate or non-usable tissue sample.

Further attempts in the art have tried using specially designed cannulasto enhance the cutting and recovery of tissue samples as well ascombining the application of a vacuum force to draw in a tissue sampleinto a biopsy cavity and then cutting the tissue contained therein. U.S.Pat. No. 4,708,147 issued to Haaga discloses a cannula for a biopsyneedle designed to cut a sample of tissue and then applying a vacuum tothe cannula such that the tissue is drawn into the cannula and thusretained therein for recovery. Additionally, U.S. Pat. No. 3,844,272issued to Banko discloses a biopsy device wherein a suction force,created by a vacuum, draws a sample of tissue into a receivingcompartment whereby two coaxial members are rotated relative to eachother so that the members essentially coact to cut off the specimen andplace it into a compartment. Such combination devices, however, fail toeither sufficiently isolate a sample or fail to draw in a sample ofsufficient size into a biopsy compartment. Additionally, suchinstruments typically are difficult to maneuver and manipulate and arenot necessarily accurate or effective enough to achieve their desiredpurpose.

Accordingly, there exists a substantial need in the art to provide atissue sample extractor capable of effectively and efficiently drawingin a suitable sample of tissue and isolating the tissue sample withinthe biopsy instrument. Additionally, there is a need for a biopsy devicethat is easy to use and can effectively be manipulated by one hand inlight of the fact that it is advantageous to perform such biopsyprocedures wherein the physician user is allowed to have an additionalfree hand. Furthermore, there is need in the art to provide a tissuesample extractor that not only provides tissue samples of sufficientsize, but allows the user to take multiple tissue samples without havingto repeatedly puncture and penetrate the tissue mass.

SUMMARY OF THE INVENTION

The present invention specifically addresses and alleviates theabove-mentioned deficiencies associated with the art. More particularly,the present invention comprises a tissue sample needle core biopsyneedle specifically designed to allow the physician user to extract asample of tissue in an effective and efficient manner while onlyrequiring the user to use one hand to operate the device. The devicecomprises a first cannula having a specifically configured, sharpened,and beveled cutting tip and biopsy-reservoir formed at its distal endwherein the biopsy reservoir is formed proximal to the cutting tip. Thefirst cannula is attachable to a conventional syringe such that thebiopsy reservoir is in fluid communication with the barrel piston of thesyringe. Axially mounted about the first cannula is a second cuttingcannula, preferably having a sharpened cutting edge formed about itsdistal end and a shoulder attached to its proximal end. The secondcannula is designed and configured to axially telescope relative thefirst cannula such that the second cannula selectively covers anduncovers the distal end of the first cannula. Disposed between theproximal ends of the first cannula and second cannula is a biasingmember, preferably a spring, which urges the second cutting cannula toadvance axially toward the distal end of the first cannula.

The syringe, the coaxially positioned first and second cannulas, andbiasing member are preferably mountable within a hand-held introducer.Preferably, the introducer is comprised of two parts, namely a handleand syringe retainer and a plunger retractor member. The handle, syringeretainer, and plunger retractor member preferably cooperate to form agun-like structure that is easy to grasp and manipulate with one hand.The handle and syringe retainer portion includes a grippable handle andmeans for retaining the syringe on the syringe retainer. The plungerretractor member includes a C-shaped member designed and configured toengage the plunger of the syringe. Additionally, the plunger retractormember includes a trigger-shaped member depending therefrom to enhancethe grippability and function of the extractor. Furthermore, the plungerretractor member includes a cam bar that is pivotally attached to a topportion of the C-shaped member. The cam bar is preferably provided witha first cam slot and a second cam abutment surface sized and configuredto selectively control the axial position of the second cannula aboutthe first cannula. The second cannula is preferably attached to ashoulder at its proximal end that is specifically designed andconfigured to engage the first cam slot and second cam abutment surface.When the shoulder is engaged with the first cam slot, the distal end ofthe second cannula is maintained in an intermediate axial positionwherein the second cannula covers the biopsy reservoir formed on thefirst cannula but leaves the cutting tip of the first cannula exposed.When the shoulder is allowed to advance to the second cam abutmentsurface, the second cannula is maintained in a distal axial positionwherein the distal end of the second cannula extends just beyond thedistal end of the first cannula. Additionally, the shoulder may bereleased altogether from the cam bar whereby the first cannula may bewithdrawn from the second cannula while maintaining the second cannularesident in the patient. Such selective withdrawal of the first cannulaenables multiple biopsies to be effectuated without multiple puncturesof the patient's tissue mass.

In order to facilitate the selective axial positioning of the secondcannula relative the first cannula, the introducer is preferablyprovided with a spring-activated detent or locking member and aplurality of locking apertures. Preferably, the locking member isdisposed upon the handle and syringe retainer while the lockingapertures are formed upon the plunger retractor member. Accordingly, theinterconnection between the locking member and a respective apertureadvantageously maintains the desired axial positions of the secondcannula relative the first cannula whereby the second cannula iscontrollably axially telescoped about the first cannula. Importantly,this interconnection detachably maintains the second cannula in aproximal axial position wherein the second cannula is axially retractedabout the biopsy reservoir of the first cannula. Such exposure of thebiopsy reservoir ultimately enables a sample to be extracted by theextractor of the present invention.

In use, the introducer is initially maintained in an operableorientation wherein the second cannula is disposed in its intermediateaxial position covering the biopsy reservoir but leaving the cutting tipof the first cannula exposed. In this position, the physician user gripsthe introducer and forces the coaxially positioned cannulas into thetissue mass. As the coaxially positioned cannulas advance into thetissue, the cutting tip of the first cannula selectively cuts andpositions the tissue over and about the biopsy reservoir covered by thesecond cannula. Once positioned within the target mass, the plungerretractor member of the introducer is manually withdrawn rearwardly withrespect to the handle and syringe retainer portion such that the secondcannula is axially retracted to its proximal axial position wherein thebiopsy reservoir of the first cannula becomes exposed to the tissuemass. Simultaneously, by such retracting or withdrawing of the plungerretractor member, the plunger of the syringe is retracted, thus creatinga vacuum within the syringe that is communicated via the axial lumen ofthe first cannula into the biopsy reservoir. Due to the created vacuum,the cut tissue is drawn into the biopsy reservoir. Having contained thetissue therein, the cam bar of the introducer may be released from theshoulder attached to the second cannula whereupon, due to the action ofthe biasing member, the second cannula rapidly axially advances from thefirst cam slot to contact the second cam abutment surfaces of the cambar, thus causing the second cannula to axially advance to its distalaxial position. During this rapid axial advancement to the distal axialposition, the cutting edge of the second cannula severs the tissuesample adjacent the biopsy reservoir and captures the same within thebiopsy reservoir of the first cannula. Having thus captured the tissuesample, the introducer may then be removed and the tissue sample may beexamined. Alternatively, the cam bar may be completely released from theshoulder of the second cannula thereby allowing the second cannula toremain resident within the tissue mass while withdrawing the firstcannula therefrom. In such arrangement, the second cannula maysubsequently be used as a passageway through which other multiple tissuesamples may be extracted without the need for further puncture of thepatient.

It is therefore an object of the present invention to provide a tissuesample extractor that will effectively and efficiently remove a portionof tissue from a tissue mass.

Another object of the present invention is to provide a tissue sampleextractor that extracts a sample of tissue by simultaneously drawing asample of tissue into a biopsy reservoir, via a vacuum, and severing andcontaining the sample within the biopsy reservoir.

Another object of the present invention is to biopsy tissue without theneed for axial advancement of a stylet into the tissue but rather, tobiopsy tissue by exact placement of the covered biopsy reservoir withinthe tissue and eliminating any further axial movement of the same.

Another object of the present invention is to provide a tissue sampleextractor that may be easily held and manipulated by one hand.

Another object of the present invention is to provide a tissue sampleextractor that allows a user to take repeated tissue samples from atissue mass without having to repeatedly puncture the tissue mass.

Another object of the present invention is to provide a tissue sampleextractor which may be easily adapted for C.T. guided and/or stereoacticbiopsy techniques.

Yet another object of the present invention is to provide a tissuesample extractor that is of simple construction, inexpensive tomanufacture, and easy to use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a tissue sample extractor according to apreferred embodiment of the present invention;

FIG. 2 is a perspective view of the tissue sample extractor as shown inuse;

FIG. 3 is a perspective view of the distal end of the first biopsycannula of the tissue sample extractor;

FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 3;

FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 3;

FIG. 6 is a perspective view of the distal end of the second cuttingcannula of the tissue sample extractor;

FIG. 7 is a perspective view of the distal ends of the first biopsycannula and the second cutting cannula wherein the first biopsy cannulais telescoped within the second cutting cannula;

FIG. 8 is a perspective view of the first and second cannulas whereinthe second cannula selectively covers a portion of the distal end of thefirst cannula;

FIG. 9 is a perspective view of the distal ends of the first cannula andsecond cannula wherein the second cannula substantially covers thedistal end of the first cannula;

FIG. 10 is an exploded view of the tissue sample extractor;

FIG. 11 is a side view of the tissue sample extractor wherein theextractor is maintained in a configuration suitable for insertion into atissue mass;

FIG. 11a is a cross-sectional view of the first and second cannulascorresponding to the position of the extractor as depicted in FIG. 11;

FIG. 12 is a side view of the extractor while positioned to obtain asample from a tissue mass;

FIG. 12a is a cross-sectional view depicting the first and secondcannulas corresponding to the position of the extractor as depicted inFIG. 12 wherein the first cannula is advanced into a tissue mass;

FIG. 13 is a side view of the extractor being maintained in a positionsuitable for recovery of the tissue sample;

FIG. 13a is a cross-sectional view of the first and second cannulascorresponding to the configuration maintained by the extractor in FIG.13;

FIG. 14 is a side view of the extractor wherein the introducer has beendisengaged from the second cannula and the first cannula and introducermay be removed therefrom; and

FIG. 14a is a cross-sectional view of the first and second cannulascorresponding to the configuration of the extractor as depicted in FIG.14 wherein the second cannula is maintained stationary in the patientand the first cannula may be withdrawn therefrom.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, and more particularly to FIG. 1, there isshown the needle core biopsy instrument or tissue sample extractor 10embodying the principles of the present invention. Theinstrument/extractor 10 comprises a first biopsy cannula 12 that isshaped and configured to be coaxially mounted within second cuttingcannula 14. Both first biopsy cannula 12 and second cutting cannula 14have proximal and distal ends, wherein the proximal end of the firstbiopsy cannula 12 is attached to first shoulder 16 and the proximal endof the second cutting cannula 14 is attached to second shoulder 18.

The distal ends of first cannula 12 and second cannula 14 are moreclearly depicted in FIGS. 3 and 6, respectively. The distal end of firstcannula 12 includes a sharpened, beveled cutting tip 44 preferablyhaving a gradual, upwardly extending slope that forms a shovel-typescooped shape. Such scoop-like shape advantageously allows for moreefficient and less traumatic tissue penetration than other cannulacutting tips currently in use. Additionally, first cannula 12 has ahollowed-out biopsy reservoir 46, also shown in FIG. 5, formed proximalthe beveled cutting tip 44. The biopsy reservoir 46 preferably is formedhaving a semi-circular shape that advantageously allows for relativelylarge, generally cylindrically-shaped tissue samples to be extractedfrom the tissue mass. As will be discussed in more detail infra, thedistal ends of the first and second cannulas 12, 14 cooperate viarelative axial movement to cut and contain a tissue sample within thebiopsy reservoir 46.

At the rear portion of biopsy reservoir 46 is a lumen or channel 13which runs the length of first cannula 12 and allows the biopsyreservoir 46 to establish fluid communication with a conventionalsyringe 22 via connector 76, as shown in FIG. 1. Such fluidcommunication between biopsy reservoir 46 and syringe 22 enhances theability of the extractor 10 to draw in and isolate a tissue sample dueto the generation of a vacuum force by the syringe 22, which shall bediscussed below. The distal end of second cannula 14 is preferablyformed having a hollow, frusto-conical shape that is designed andconfigured to allow first cannula 12 to axially pass therethrough. Thedistal rim 48a of the frusto-conical portion 48 is sharpened so thatdistal rim 48a may cut and contain a tissue sample disposed withinbiopsy reservoir 46 when the rim 48a is axially passed across the biopsyreservoir 46 of the first cannula 12.

As shown in FIG. 7, the distal end of first cannula 12 freely passes,via axial movement, through the distal end 48 of second cannula 14.Second cannula 14 also preferably includes a barrel section 50 thatserves as a sleeve to protect and contain a biopsy sample containedwithin a biopsy reservoir 46 when such sample is extracted from a tissuemass. The first and second cannulas may be formed in differing lengthsand diameters to be utilized for a wide variety of tissue samplingapplications such as breast, prostate, deep body, lung and other softtissue biopsies.

In addition to being coaxially positioned relative to one another, firstcannula 12 and second cannula 14 are maintained in an arrangementwhereby the second cannula is constantly urged forward by biasing member20, more clearly depicted in FIG. 1. Preferably, biasing member 20comprises a spring that is interposed between the first shoulder 16formed on the first cannula 12 and second shoulder 18 formed on thesecond cannula 14. The distally urging biasing force exerted by spring20 forces the second shoulder 18, and hence second cannula 14, toaxially advance upon the first cannula 12.

In order to selectively control the position of the second cannula 14relative to first cannula 12, the extractor 10 of the present inventionadvantageously incorporates the use of introducer 26. In the preferredembodiment, the introducer 26 is fabricated from polymer and/or metalmaterials that may be sterilized or disposed of, such materials beingwell known to those skilled in the art. Preferably, the introducer 26 iscomprised of two parts, namely a handle and syringe retainer 28 and aplunger retractor member 30, more clearly depicted in FIG. 10. Thehandle and syringe retainer 28 comprises a handle portion as well asstructure sized and configured for detachably interconnecting with theconventional syringe 22. More specifically, the syringe retainer 28preferably includes first and second syringe support members 58, 60 andsyringe support collar 62 which engage the syringe 22 and firmly holdthe syringe 22 in position. Additionally, there is provided slot 56 thatis designed and configured to detachably engage with rim 22a on syringe22 so as to further provide secure attachment with syringe retainer 28.

The plunger retractor member 30 of introducer 26 comprises a generallyC-shaped member having a trigger member 32 depending therefrom. The rearportion of the plunger retractor member 30 has a slot 52 to receiveplunger 24 on syringe 22. As will be discussed, slot 52 provides meansfor retracting the plunger 24 such that a vacuum is created in syringe22 and ultimately in biopsy reservoir 46 via lumen 13 shown in FIG. 3.

Mounted adjacent the top portion of the retractor member 30 is cam bar34, which is preferably pivotally mounted 36 thereon. As more clearlyillustrated in FIG. 10, the cam bar 34 includes a first cam slot 38 anda second cam abutment shoulder or surface 40. Additionally, cam bar 34has a groove 42 which allows the coaxially positioned first cannula 12and second cannula 14 to pass therethrough. As will be discussed, thefirst cam slot 38 and second cam abutment surface 40 provide means foradjusting the relative axial position of second cannula 14 with respectto first cannula 12.

The handle and syringe retainer 28 and plunger retractor member 30 arepreferably connected to one another via a sliding-type engagement. Morespecifically, the plunger retractor member 30 is movably mounted ontothe rear portion of syringe retainer 28 such that surface 30a isreceived upon upper guideway 64 and flanked by elongate guide members 66and 68. Additionally, surface 30b is received within lower guideway slot70 such that trigger member 32 protrudes from the handle and syringeretainer 28 to form a gun-type configuration. In addition, the handleand syringe retainer 28 further include a spring-activated detent orlocking member 72 to engage apertures formed on surface 30c of theplunger retractor member 30, said apertures being more clearly depictedas 74a,b in FIGS. 11, 12, 13, and 14. Such spring-activated lockingmember 72, when aligned with locking apertures 74a,b, provide means forpositioning the handle and syringe retainer 28 with respect to theplunger retractor member 30 such that desired depths and axialpositioning of the cannulas 12, 14 may be more easily attained whenusing the extractor 10. Importantly spring-activated locking member 72,when aligned with locking aperture 74b, maintains the introducer 26 inan orientation that causes second cannula 14 to axially retract aboutbiopsy reservoir 46 in a proximal axial position.

Having thus described the structure of the biopsy instrument/extractor10 of the present invention, the operation of the same shall now bedescribed with specific reference to FIGS. 11 through 14. Preparatoryfor use, the first and second cannulas 12 and 14 are coaxiallypositioned with biasing member 20 interposed between the shoulders 16and 18. The proximal end 76 of the first cannula 12 may then be attachedto the distal end of the syringe 22. As shown in FIG. 11, the syringe 22is mounted within handle and syringe retainer 28 with plunger 24 beingreceived in slot 52 of the plunger retractor member 30. Additionally,cam bar 34 is positioned such that second shoulder 18 is received withinfirst cam slot 38. Additionally, the, spring-activated locking member 72is received within locking aperture 74a in such a manner that relativeorientation or position of the handle 28 and plunger retractor member 30is maintained unless otherwise manually adjusted. FIG. 11a depicts thecorresponding axial position (i.e., the intermediate axial position)between first cannula 12 and second cannula 14 while the introducer 26is maintained in the initial orientation depicted in FIG. 11. Asillustrated, the second cannula 14 selectively covers biopsy reservoir46 while beveled cutting tip 44 axially protrudes or extend therebeyond.

While the introducer 26 and first and second cannulas 12, 14 aremaintained in the orientation and relative axial position depicted inFIG. 11 and FIG. 11a, the introducer 26 is then gripped, as shown inFIG. 2, and the first and second cannulas are manually pressed orinserted into a tissue mass from which a sample is to be extracted. Asmentioned above, the introducer 26, namely the combination of handle andsyringe retainer 28 and plunger retractor member 30, is formed to have agun-like shape that allows the user to manually insert the coaxiallypositioned cannulas 12, 14 while maintained in this intermediate axialposition and ultimately extract a sample of tissue using only one hand.Such design advantageously allows the physician user to utilize theirother hand so as to manipulate the tissue or perform some other functionas may be required.

During insertion of the first and second cannulas 12, 14 through thetissue, the user forces both interconnected portions 28, 30 of theintroducer 26 into the tissue in a direction indicated by the arrows "A"in FIG. 11. As should be noted, locking member 72 is engaged withinaperture 74a during such insertion to prevent any relative axialmovement between the handle 28 and plunger retractor member 30.Additionally, during such insertion the introducer 26 forces thecannulas 12, 14 into the tissue whereby the sharpened beveled cuttingtip 44 is forced directly into the tissue, and the cutting tip 44 of thefirst cannula simultaneously cuts the tissue and positions the cuttissue adjacent its periphery so as to overlie the second cannula 14adjacent the biopsy reservoir 46.

Once embedded within the tissue and having cut the tissue sample, theintroducer 26 is manipulated such that the handle and syringe retainer28 of the introducer 26 remains stationary while the plunger retractormember 30 is rearwardly retracted in the direction indicated by "B". Theplunger retractor member 30 is retracted, via manipulation of triggermember 32, such that spring-activated locking member 72 is released(i.e., overcome) from locking aperture 74a and subsequently engage withlocking aperture 74b as shown in FIG. 12. Due to the engagement of thesecond shoulder 18 with the cam slot 30 of the cam bar 34, during suchrearward movement, the second cannula 14 axially retracts relative thefirst cannula 12 and is disposed in its proximal axial position whereinthe biopsy reservoir 46 is exposed to the tissue mass 82, as depicted inFIG. 12a. Accordingly, the axial retraction of the frusto-conical endportion 48 of second cannula 14 allows such cut tissue mass 82 to bereceived within the biopsy reservoir 46. Advantageously, during suchretraction of the plunger retractor member 30 relative to handle andsyringe retainer 23, a vacuum is generated in syringe 22 such that thepreviously cut tissue mass 82 is drawn downwardly into the biopsyreservoir 46 as depicted in FIG. 12a.

Having effectively drawn the mass of tissue 82 to be extracted into thebiopsy reservoir 46, the cam bar 34 is manually raised in the directionindicated by the letter "D" in FIG. 13 such that the second shoulder 18is released from first cam slot 38. Spring member 20 preferably providessufficient force such that upon release from first cam slot 38 thesecond cannula 14 rapidly axially advances with sufficient force tocause the sharpened distal end 48a of the second cannula 14 to sever andretain the tissue sample 82a to be extracted within biopsy reservoir 46.Such forward axial movement of the second cannula 12 continues until thesecond shoulder 18 abuts the second cam abutment surface 40. Thecross-sectional view depicting this distal axial position of the secondcannula 14 depicted in FIG. 13a, which corresponds with the abutmentbetween second shoulder 18 and second cam abutment surface 40, as shownin FIG. 13. As shown, in this distal axial position, the second cannula14 securely captures the cut tissue mass 82a within the biopsyreservoir.

Having thus isolated the tissue sample 82a from tissue mass 82, theextractor 10, and hence first and second cannulas 12, 14, may both beremoved from the tissue mass by withdrawal of the extractor 10 where thetissue sample 82a may be recovered from the biopsy reservoir 46 andsubsequently examined. Alternatively, as illustrated in FIG. 14, thepresent invention provides that cam bar 34 may be raised even furtherabout pivot 36 to allow second shoulder 18, and thus second cannula 14,to remain in place while introducer 26, syringe 22, and first cannula 12may be manually withdrawn in the direction indicated by the arrow "E".Advantageously, by allowing the second cannula 14 to remain stationarywithin tissue mass 82, the user, if desired, may make further tissuesample extractions through second cannula 14 in the manner describedabove. Advantageously, by using the extractor 10 of the presentinvention, the user will not have to make repeated punctures into thetissue which will thus facilitate the extraction of multiple sampleswhile subjecting the subject to a less traumatic experience as comparedto other devices known in the art.

There has thus been disclosed a tissue sample extractor, with variouspreferred embodiments thereof, having been described in detail with thevarious advantages being set forth. It is understood, however, thatequivalents are possible and that variations in structure may be madethat fall within the underlying principles of the present invention.

What is claimed is:
 1. A tissue sample extractor comprising:a) a firstbiopsy cannula having proximal and distal ends, said first biopsycannula being generally circular in cross-section and having a lumenformed therein, said distal end having a sharpened beveled cutting tipand a biopsy reservoir formed thereon, said biopsy reservoir beingformed proximal said cutting tip; b) a second cutting cannula havingproximal and distal ends, said second cutting cannula being axiallymounted about said first biopsy cannula such that said first biopsycannula is partially telescoped within said second cutting cannula, saiddistal end of said second cutting cannula having a sharpened cuttingedge formed thereon; c) an introducer, said introducer being configuredto simultaneously and detachably engage with said first biopsy cannulaand said second cutting cannula; and d) wherein said introducercontrollably moves said second cutting cannula about said first biopsycannula such that said distal end of said second cutting cannulaselectively covers and uncovers said distal end of said first biopsycannula.
 2. The tissue sample extractor of claim 1 wherein saidintroducer is configured to urge said second cutting cannula toselectively cover said biopsy reservoir and leave said sharpened beveledtip uncovered in a first intermediate position and to allow said secondcutting cannula to uncover both sharpened bevel tip and biopsy reservoirin a second proximal position.
 3. The tissue sample extractor of claim 2wherein said introducer is further configured to urge said secondcutting cannula to extend beyond and axially surround said distal end ofsaid first biopsy cannula in a third distal position.
 4. The tissuesample extractor of claim 3 wherein said extractor further comprises adevice for creating a vacuum, said device being attached to and in fluidcommunication with said proximal end of said first biopsy cannula viathe lumen formed therein, said device being configured to cause a vacuumto be generated within said first biopsy cannula when said second biopsycannula is withdrawn from over the biopsy reservoir of said firstcannula, said vacuum being sufficiently strong to cause a portion ofsaid tissue to be drawn into said biopsy reservoir.
 5. The tissue sampleextractor of claim 4 wherein said device for creating a vacuum isinterconnected with said introducer such that said introducersimultaneously causes said device for creating a vacuum to generate saidvacuum when said second cutting cannula is urged into said secondproximal position.
 6. The tissue sample extractor of claim 3 whereinsaid introducer further includes an apparatus for detachably maintainingsaid second cutting cannula in said intermediate and distal positions.7. The tissue sample extractor of claim 6 wherein said first biopsycannula, said second cutting cannula, and said introducer are configuredsuch that when said first biopsy cannula is advanced into said tissueand said second cutting cannula is withdrawn to said second proximalposition, said second cutting cannula may then be advanced into saidthird distal position such that said second cutting cannula cuts andisolates a tissue sample within said biopsy reservoir.
 8. A tissuesample extractor comprising:a) a first biopsy cannula having proximaland distal ends, said proximal end having a first shoulder attachedthereto, said distal end having a sharpened beveled cutting tip and abiopsy reservoir formed thereon, said biopsy reservoir being formedproximal said cutting tip; b) a device for creating a vacuum, saiddevice being attached to said first shoulder and in fluid communicationwith said biopsy reservoir of said first biopsy cannula via a vacuumconduit; c) a second cutting cannula having proximal and distal ends,said proximal end having a second shoulder attached thereto, said distalend having a sharpened cutting edge formed thereon, said second cuttingcannula being axially mounted about said first biopsy cannula such thatsaid first biopsy cannula is partially telescoped within said secondcutting cannula; d) a biasing member disposed between said firstshoulder and said second shoulder such that said second shoulder urgessaid second cutting cannula to distally advance about said first biopsycannula; and e) an introducer, said introducer being detachably engagedwith said device for creating a vacuum and said second shoulder of saidsecond cutting cannula, said introducer being attached to said secondcutting cannula and said device for creating a vacuum such that saidintroducer controllably adjusts the relative positions of said first andsecond cannulas such that said distal end of said second cutting cannulais selectively movable about said first biopsy cannula.
 9. The tissuesample extractor of claim 8 wherein:a) said device for creating a vacuumcomprises a conventional syringe and plunger; b) said biasing memberdisposed between said first shoulder and said second shoulder comprisesa spring member; and c) said introducer comprises a handle and syringeretainer in combination with a plunger retractor member, said handle,said syringe retainer, and said plunger retractor member cooperating toform a gun-like member.
 10. The tissue sample extractor of claim 9wherein said plunger retractor member comprises a generally C-shapedmember having a trigger-shaped member depending therefrom and a slotformed thereon to engage said plunger, said generally C-shaped memberhaving a cam bar pivotally attached along a top portion thereof, saidcam bar having a first cam slot and a second cam abutment surface, saidfirst cam slot and said second cam abutment surface being configured todetachably engage with said second shoulder of said second cuttingcannula, said first cam slot and said second cam abutment surface beingspaced such that said second cutting cannula is urged forward about saidfirst biopsy cannula such that said distal end of said first biopsycannula is selectively covered by said second cutting cannula.
 11. Thetissue sample extractor of claim 10 wherein:a) said first cam slotdetachably engages said second shoulder such that said second cuttingcannula selectively covers said biopsy reservoir and leaves saidsharpened beveled cutting tip uncovered; and b) said second cam abutmentsurface detachably engages said second shoulder such that said secondcutting cannula covers both said biopsy reservoir and said sharpenedbeveled cutting tip.
 12. The tissue sample extractor of claim 11 whereinsaid introducer may be used by a single hand.
 13. The tissue sampleextractor of claim 12 wherein said biasing member and said introducercooperate to allow said first biopsy cannula to advance through saidsecond cutting cannula such that said biopsy reservoir and sharpenedbeveled cutting tip are exposed when said first biopsy cannula and saidsecond cutting cannula are inserted into a tissue mass.
 14. The tissuesample extractor of claim 13 wherein said cam bar is configured to bemanually adjustable such that said second shoulder is urged from saidfirst cam slot to said second cam abutment surface, said cam bar beingfurther manually adjustable such that said second shoulder is releasablyfrom said second cam abutment surface such that said cutting cannula isconfigured to be axially removable from said second cutting cannula. 15.The tissue sample extractor of claim 14 wherein when said first biopsycannula and said second cutting cannula are embedded within a tissuemass and said biopsy reservoir is exposed by withdrawal of secondcutting cannula, said cam bar is manually adjustable such that saidbiasing member forces said second cutting cannula to distally advanceover said biopsy reservoir of said first biopsy cannula wherein saiddistal advancement forces said second cutting cannula to sever a portionof said tissue and contain said portion within said biopsy reservoir.16. The tissue sample extractor of claim 15 wherein said cam bar isfurther configured to be manually adjustable such that said biasingmember forces said second cutting cannula to become embedded within saidtissue mass, said second cutting cannula being so embedded that at leastone additional sample of tissue may be extracted through said secondcutting cannula.
 17. The tissue sample extractor as recited in claim 4wherein said device for creating a vacuum comprises a disposablesyringe.
 18. A method for extracting a sample of tissue from a tissuemass, the method comprising the steps of:a) inserting a first and asecond cannula within the tissue mass, said first cannula beingpartially telescoped within said second cannula, said first cannulahaving a sharpened beveled cutting tip and a biopsy reservoir formed ata distal end thereof, said second cannula having a sharpened cuttingedge formed about a distal end thereof, said first cannula being sotelescoped within said second cannula such that said sharpened beveledbutting tip protrudes from said second cannula while said biopsyreservoir remains covered by said second cannula; b) withdrawing saidsecond cutting cannula to expose biopsy reservoir in said first cannulaby manipulating a trigger on a C-shaped retraction member; c)simultaneously applying a vacuum force to the interior of said fistcannula such that a sample of tissue is drawn into said biopsyreservoir, a cam then causing the retraction member to release thesecond cutting cannula, thereby allowing a biasing member to axiallyadvance said second cannula about said first cannula such that saidsecond cutting cannula severs said tissue collected about said biopsyreservoir and encases said sample within said biopsy reservoir; and d)removing said sample encased within said biopsy reservoir.
 19. Themethod of claim 1 further comprising the step of simultaneouslywithdrawing said second cannula relative to said first cannula andcausing said vacuum to be produced within said first cannula.
 20. Themethod of claim 1 wherein the step of applying a vacuum force comprisesapplying a vacuum force via a conventional syringe.
 21. The method ofclaim 1 wherein said introducer is configured to be used by a singlehand of the user.